Among other things, coordinate measuring machines (“CMMs,” also known as surface scanning measuring machines) measure geometry and surface profiles, or verify the topography of known surfaces. For example, a CMM may measure the topological profile of a propeller to ensure that its surface is appropriately sized and shaped for its specified task (e.g., moving a 24-foot boat at pre-specified speeds through salt water).
To that end, conventional CMMs typically have a base directly connected with and supporting a movable assembly having a probe that directly contacts and moves along a surface of an object being measured. The base also supports the object being measured. The probe typically is movable upwardly and downwardly toward and away from the base (known in the art as “Z-axis movement”). Purity of the axis is important in obtaining accurate results.